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US 5,347,852 AGranted
On-line rheological measurements for process control
AssigneeRheometrics, Inc.
InventorPaul G. Mode
Life of this patent
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AssigneeRheometrics, Inc.
InventorPaul G. Mode
Estimating the term…
On-line rheological measurements are made utilizing a rheometer of the type in which a first metering pump delivers diverted melt from a process main stream to a capillary passage and a second metering pump returns the diverted melt from the capillary passage to the process main stream and the viscosity of the diverted melt is measured by controlling the rate of flow of the melt through the capillary passage to maintain constant the pressure drop between spaced apart locations along the capillary passage and measuring the temperature of the melt in the capillary passage. The measurements may be made while controlling the speed of the second metering pump independent of the speed of the first metering pump to maintain the pressure at the exit of the capillary passage essentially constant. A parallel flow passage has an inlet placed between the first metering pump and the entrance to the capillary passage, in close juxtaposition with the entrance and an outlet placed between the exit from the capillary passage and the second metering pump, and a valve in the parallel flow passage is operated so that diverted melt selectively is passed through the parallel flow passage to attain a relatively quick response and relatively short residence time of the diverted melt in the rheometer.
An improvement in an apparatus for conducting an on-line rheological measurement in a process melt in a process main stream so as to provide process control information based upon the viscosity of the process melt, utilizing a rheometer of the type in which a first metering pump delivers diverted melt from a first conduit, communicating with the process main stream and the first metering pump, to an entrance of a capillary passage and a second metering pump delivers the diverted melt from an exit of the capillary passage to a second conduit communicating with the second metering pump, and measuring means for measuring the viscosity of the diverted melt in the capillary passage, the improvement comprising:
An improvement in a method for conducting an on-line rheological measurement in a process melt in a process main stream so as to provide process control information based upon the viscosity of the process melt, utilizing a rheometer of the type in which a first metering pump delivers diverted melt from a first conduit, communicating with the process main stream and the first metering pump, to an entrance of a capillary passage and a second metering pump delivers the diverted melt from an exit of the capillary passage to a second conduit communicating with the second metering pump, and measuring means for measuring the viscosity of the diverted melt in the capillary passage, the improvement comprising:
Dependencies are inferred from the claim text.